Double-gyro inclinometer



L. B. SPERRY.

DOUBLE GYRo INCLINOMTER.

AFPLICATION FILED APR. 1B. l9l8.

1 ,$09,489. Patented July 8, 1919.

, UNITED sTATEs PATENT oEEIeE.

LAWRENCE B. SPERRY, OF BROOKLYN, NEW YORK, ASSIGNOR TO THE SPERRYGY'ROSCOPE COMPANY, OF BROOKLYN, NEW YORK, A CORPORATION 0F NEW YORK.

DOUBLE-GYRO INCLINOMETER.

Specification of Letters Patent.

Patented July 8, 1919.

To all ywlw/rt it may fron/:cru

Be it known that I, LAWRENCE ll. SrEuuY, a citizen of the United Statesof America, residing at 1505 Albemarle road, Brooklyn, in the county ofKings and State of New York, have invented certain new and usefullmproveuu-,nts in Double-Gyro Inclinometers, of which the following is aspecification.

This invention relates to inclinometers, more specifically toinclinometers of the type employing a rotating wheel or top to establisha reference line and especially adapted for use on aeroplanes.

I have discovered that while a rotating wheel or top will maintain itsrotational axis substantialy vertical when the aeroplane, or

' other device on which the top is employed,

is turning in azimuth in the same direction as the top is rotating, therotational axis of the latter drops out of vertical position when thevehicle is turning in the opposite direction. The last mentioned actionrenders the device unreliable and under the conditions assumedpractically destroys its utility.

While the problem presented under the above assumed conditions might besolved by employing a' damping, force impressing or other similar means,it should be n oted that by the provision of any such means the devicewould lose its chief characteristic, i. e., simplicity. I solve theproblem by employing two oppositelyl rotating wheels or tops, so that atleast one will furnish a true reference line at all times.

Referring to the drawings in which, what I now consider to be thepreferred form of my invention, are shown:

Figure 1 is a plan view of the device constructed in accordance with myinvention, the cover of one of the gyroscopes being removed.

Fig. 2 is a cross section on approximately line 2-2 of Fig. 3.

Fig.'3 is a diagrammatic view, partly in section and on a smaller scale,of m invention showing the means used to contlnuously withdraw air fromthe interior of the casmg.

Fig. 4 is a plan view showing the graduations on cover 8.

Each top is shown as comprising a rotor or flywheel 1, having a heavyring 2 and a cut-out under portion 3. In the center of the top is apoint 4 which supports the top for rotation about a normally verticalaxis and at the same time allows the top freedom of movement about bothhorizontal axes intersecting at said point. lVhile in the common orordinary form of top the center of gravity is located above the point ofsupport I` prefer to so design the tops, employed in my invention,- thatthe center of gravity is located very close to but slightly below thepoint of support 4. By virtue of this design each top standssubstantially in neutral or indifferent equilibrium when at rest wherebya long period of oscillation is secured.

Each top is preferably provided with a spindle 5 which acts as a pointeror indicator, and coperates with radial graduations and with circulargraduations 7 on the transparent covers 8 to indicate both the angle anddirection of inclination of the vehicle on which the instrument ismounted. Each cover is securedwithin a cap 9 threaded into thetop of thecasing proper 10 or 10', the joint 10() being tightly packed.Illuminating means such as lamps 70 and 71 may be provided, if desired.Each casing surrounds its rotor and supports the sameK on a post 11secured to the bottom of the casing. Casing 10, together with companioncase 10 are shown as resiliently supported from a ring or frame 12 bymeans of a plurality of rods 13, 13 and 13 which are adjustably threadedto said frame and locked thereto by lock nuts 14, the casings 'beingsupported on said posts by springs 15 resting on washers 16 or the like.Preferably a downwardly acting spring 17 is placed above said ring andacts between the cap 18 and the ring so that jars will not affect the4apparatus. Preferabl three such supporting rods are provided or thegyroscopic device. A bracket 72 secured to ring 12 may be used to attachthe apparatus to the aeroplane or other vehicle.

For revolving each rotor I prefer to provide means for continuouslywithdrawing 'air from the interiorof its casing, relying upon theentrance of air into the casing in a proper direction and location torevolve the rotor. F or this purpose I have provided valves or otheropenings 18 18" through which the air is exhausted from the casings inany manner, preferably in 'the manner hereinafter descri ed'.

One or more openings shaped in. the form of approximately tangentialnozzles 19, 20,

21 and 22, are provided in the casing 10 in the plane of the rotor 2.The rotor in casing 10 is provided with bucket'sor vanes 23 located inthe plane of said .nozzle and adapted to receive thejets of air issuingtherefrom. Preferably said vanes are formed by incisions in theperiphery of the rotor. The casing 10 and its rotor 3 are provided withnozzles 19 to 22 and buckets 23 similar to the corresponding` struct-ureof casing 10 and its rotor 3 except that the former extend in adirection opposite the last mentioned nozzles and buckets. tors 2, 2will be rotated-in opposite directions.

Each post 11 is shown as comprising a central supporting stem 20 havingan axial bore 21 in which is located a spring 22 supporting a rod 23.Said rod is provided adjacent its top with a tapered or concave recess24 in which the point 4 attached to the top l rests. Preferably saidrecess is flat at the bottom portion 80 at which point the wall 81 issubstantially perpendicular for a short distance.

As above stated I employ a plurality of tops 1 and 1 which are driven inopposite directions as indicated by the arrows in Fig. l. The reason foremploying two oppositely rotating tops is, as previously stated, toinsure -having at least one of the tops cor` rect at all times. Forinstance, if the aeroplane on which the apparatus was mounted wasturning in the direction of arrow C (Fig. l) top 1, which is shown asrotating in the opposite direction, would have a tendency to flop over,as indicated, while top 1 would remain unaffected. Similarly, if theaeroplane were turning in the other direction, top l would straighterup, while top l would tend to turn over. nShe casings 10 and 10inclosing the two tops may be formed as one or connected by pipe 50.Each casing may be provided with an outlet valve 18 and 18, which may becon-v nected to the air exhausting device.

For exhausting the air from the casings, I prefer to employ a device 55somewhat similar to a Venturi tube. Said device may comprise a tubularmember with a restricted passage 56 therein, each end of the membertapering outwardly, Fig. 3. If the aircraft is flying in the directionindicated by the arrow a in said figure, the air will flow with greatspeed through the said tube and restricted passage, thereby reducing thepressure to a marked extent adjacent said passage. At or adjacent saidrestricted passage is located a second small tube 57 which is connectedto the valves 18 and 18 by means of a pipe 58. having a branch pipe 519.Pipe 58 is shown tappe-d into tube Thus the ro- 57 adjacent a restrictedpassage G0 therein as indicated in Fig. 3, whereby .a doublerarefactionlof air, soto speak, is produced. By properly manipulatingthe valves 18', 18 and a valve 110, provided in the pipe 50 either orboth of the tops may be disconnected from the air exhausting device.

In accordance with they provisons of the patent statutes, I have hereindescribed the principle of operation of my invention, together with theapparatus, which I now consider to represent the best embodimentthereof, but I desire to have it understood that the apparatus shown isonly illustrative and that the invention can be carried out by othermeans. Also, while it is designed to use the various features andelements in the combination and relations described, some of these maybe altered and others omitted without interfering withv the more generalresults outlined and the invention extends to such use.

Having described my invention, what I claim and desire to secure by.Letters Pat ent is:

l l. An inclinometer for aeroplanes comr1s1n0 a air of omt-su orted groseo 1c e p e.

rotors having -normally vertical spinning axes and air turbine means fordriving said rotors in opposite directions.

2. An inclinometer for aeroplanes comprising a pair of tops, aninclosing lcasing for each top, means for withdrawing air from saidcasings, oppositely positioned buckets or vanes on the tops and a nozzleadjacent each top connecting .the interior of the casing with theoutside air.

' 3. rIhe combination with an aeroplane, of a Venturi tube thereon, acasing connected to said tube, a plurality of tops within said casing,buckets or vanes on said tops and openings through the casing adjacenteach top and oppositely directed whereby opposite rotation of the topsis secured.

4. In gyroscopic apparatus, the combination with a plurality of rotors,communicating inclosing means for said rotors, a

plurality of outlets from said casing at least one for each rotor, meansfor exhausting air through said outlets and an air admitting nozzleforeach rotor.

5. In gyroscopic apparatus, the combination with a plurality of rotors,communicating inclosingmeans for said rotors, a plurality of outletsfrom said casing, means for exhausting air through said outlets andmeans for shutting off that portionof the casing adjacent a rotor from aportion of the apparatus adjacent another rotor.

In testimonyI whereof I have affixed my' signature.

LAWRENCE B. SPERRY.

